Are the proceeds from previous work in selling alcohol lawful after stopping and working in another field, and how can these funds be purified?

Funds acquired through unlawful means must be disposed of by spending them on general Muslim welfare, such as for the poor or digging wells. If lawful and unlawful money are mixed, then one must investigate and dispose of the unlawful portion. If all the money is unlawful, then all of it must be disposed of. However, if the principal assets are permissible but the trade is unlawful, then the unlawful profits must be disposed of, while the principal capital remains permissible.